Polygon Intersection Based Algorithm for Fuzzy Set Compatibility Calculations

Abstract—PFSQL is an extension of the SQL language that allows usage of fuzzy logic in SQL queries. In query statements, variables can take both fuzzy and non-fuzzy values. Normally, different types of values cannot be compared directly. Therefore, it is necessary to implement fuzzy compatibility calculation to solve this problem. This paper proposes a method of fuzzy compatibility calculation implementation that determines compatibility degree of two fuzzy sets. The compatibility value is calculated using polygon intersection algorithm. To prove the correctness of the proposed method, the application has been developed and tested with 360 compatibility cases of different randomly generated fuzzy values. The experimental results show that our algorithms can handle various types of intersections between any two fuzzy sets.